The puddling or the refining of metal
was a process that consisted of the heating of a
reverberatory oven and at high temperatures the
ingots of steel melted to eliminate part of its
carbon component and the slag that had been
introduced during the casting process. In these
puddling furnaces the metal did not come into direct
contact with the coke carbon, instead it received
the heat reflected on the walls of the furnace in
order to avoid the addition of impurities. Once the
ingots were completely melted the puddling or the
arm movement began, stirring the liquid with a spit
so that, when the slag was mixed with the metal, it
was eliminated through oxidisation.

The wrought iron or
soft iron

The ingots of melted steel obtained
from the blast furnace were transformed into soft
steel, also called wrought iron, reducing its
content of carbon and eliminating at the same time
by oxidisation a great part of its impurities such
as sulphur, phosphorous, manganese and silicon. This
process, which was mainly done through puddling in
the reverberatory furnaces, was completed by
submitting the "billets" of steel obtained to the
percussion of the steam hammer, eliminating in this
way the slag that had been mixed with the steel
during the initial fusion.